Figure



March 31, 1964 H. A. A. EXNER FOUNTAIN PEN WITH A FLEXIBLE CAPILLARY MATERIAL IN INK-CONTAINER Filed May l 1962 3 SheeiAzs-Sheet 1 /rnrhnhnrrrrrrrrrrrrf FIGZ.

INVENIOR HELLMUTH A. EXNER ATTORNEY March 31, 1964 H. A. A. ExNER 3,126,874

FOUNTAIN PEN WITH A FLEXIBLE CAPILLARY MATERIAL IN INK CONTAINER Filed May l 1962 3 Sheets-Sheet 2 44 INVENTOR HELLMUTH A. ExNER BY M,

ATTORNEY FIGS FIGM

March 31, 1964 H. A. A. EXNER FOUNTAIN PEN WITH A 'FLEXIBLE CAPILLARY MATERIAL IN INK CONTAINER 5 Sheets-Sheet 3 Filed May l, 1962 FIGA?) )I INVENTOR HELLMUTH A. EXNER ATTORNEY United States Patent Oliee 3,126,874 Patented Mar. 3l, 1964 3,126,874 FOUNTAllN PEN Wli'iH A FLEXWLE CAPELLARY MATERIAL IN HNK CONTANER Hellmuth A. A.. Exner, Laprida 5141, Mar del Plata, Argentina Filed May l, 1952, Ser. No. 191,483 Claims priority, application Germany inne 20, 1%1 l2 Claims. (Cl. 12d- 44) This invention refers to a fountain pen of the type provided with a piston for letting ink into same, and has as its primary object the elimination of existing unreliable compensator-chambers which are usually found in fountain pens and also to obviate the loss of ink caused by the varying of atmospheric and heat pressures.

To accomplish this objective, the inside of the ink container is furnshed with a flexible capillary ink absorbing material, for example, foam plastic with open cells which is attached at one end to the ink capillary channels and at the other end to the pump plunger of the filling mechanism.. This attachment is made by soldering, welding, pasting or in any other way, such 'as by elastic force or by means of a pressure spring, so that when the pump plunger is `forced against the ink capillary channels the iiexible foam material is pressed together and the air or ink contained in same is forced out. ln fountain pens of this type the air and ink are forced through closeable ink openings situated near the Writing point and when pulling the pump plunger back, new ink is let into the iiexible capillary material through the above-mentioned closable ink openings and the capillary channels. The pump plunger just before it reaches its backward position, leaves an opening free to compensate for the variation of the atmospheric and heat pressures, so that these variations of pressure cannot interfere with the flow of ink to the writing point. This latter condition is often the case with half filled fountain pens of normal make when changed from a cool position to la warm position, for example, caused by: placing them in the sun or other heat; where the compensator chambers are too small; and by the abnormal expansion. of the air bubble in the closed ink container which causes the ink to iiow out to the compensator chambers.

in fountain pens of the type described, in order to facilitate the opening or closing of the above mentioned closable ink openings, the base of the guide cylinder and also the base of the writing tube are provided with threads to make possible the screwing of the base of the Writing tube into the guide cylinder. Also, there is provided on the base of the writing tube openings at the upper part thereof, Le., the part that is screwed into the guide cylinder. Further, on the base of the writing tube there is provided a threaded or hexagonal head which -ts in a keylock that is constructed in the push-button of the cap or cover so that when the writing mechanism is taken out of the pen body the said keylock the push-button is placed on the threaded hea-d of the writing tube base and used as a key to rotate the writing tube and facilitate an easy opening and closing of said ink openings.

In la second filling system, the ink container is made of flexible material and is also filled with flexible foam plastic or other ink absorbing capillary material, and by unscrewing the push-button which is provided with a depend.

ing conical extension, the same -ts into an elastic or plastic tube in the upper neck of the ink container and serves the function of an eihcient retention valve which in a normal way, that is to say, when the push-button is firmly screwed, is always open to ensure the variation of the atmospheric `and heat pressures. By `squeezing or pressing the `flexible ink container together, the air in the same will be forced out through the just-described retention valve and by lessening the pressure on the ink container,

the writing ink will, in a manner similar to that previously described, enter the ink openings constructed in the base of the writing tube.

Another manner of preventing leakage of ink from the upper air vent when the ink container is filled with ink, is to provide in the neck of the ink container above a perforated disc and the flexible foam plastic material, a floating valve which also serves as a retention valve. Beneath the floating valve, there is located an elastic counterpressure ring provided with a plurality of upwardly extending projections to ensure the passage of air for variations of the atmospheric and heat pressures. The perforated disc which is located above the flexible capillary material in the ink container prevents said material from interfering with the retention valve.

in fountain pens provided with `breather openings in the upper part of the ink container, but constructed with a rigid ink container and with rigid or ilexible capillary material, and constructed Without aspiration means and retention valves and with or without the closeable ink openings in the writing tube base, the means for letting ink into the ink container can be obtained by pressure, which is produced by a iiexible inlcwell or an inkwell provided-with pumping means. In such cases, the inkwell is [furnished with suitable seating means into which the lower part of the Writing tube or the guide cylinder is rmly placed. Also, the means for letting ink into the ink container may take the form of an instrument or a cap for an ordinary inlcwell, furnished with a retention valve, which can be applied -to the breather openings lat the top of the ink container, which sucks the air out of same.

An example of the construction of the invention is shown in the drawing, which is as follows:

FIGURE l is a longitudinal view of a fountain pen with retractable writing tubes, and with the pump plunger in its backward position, and therefore the flexible capillary foamy material in the ink container fully expanded leaving the opening free for the variations of the atmospheric and heat pressures, and with the writing mechanism in its writing position.

FlGURE 2 is a longitudinal View of the writing mechanism with the purnp plunger in its forward position and therefore with the capillary foam material pressed fully together and with the ink openings in open position, i.e., with the writing tube base unscrewed suiiiciently to leave the ink openings free.

FIGURE 3 is a longitudinal enlarged View of the lower portion of the instrument shown in FIGURE 2 with the writing tube base unscrewed and the ink openings open. Also shown is the capillary ink oW above the ink capillary guides to the flexible capillary material of the ink container.

FIGURE 4 is a sectional View taken on line 4 4 of FGURE 3 of the said hexagonal head on the writing tube base.

FIGURE 5 is a sectional View taken on line 5 5 of FGUMRE 3, of the said capillary ink trunk supply showing the radial capillmy channels.

FIGURE 6 shows the writing mechanism with a flexible ink container lled with flexible capillary material and with the conical retention valve constructed in the of the flexible capillary material in same which prevents the deterioration of same caused by lateral pulsation and resists longitudinal pressures.

FIGURE 9 is a longitudinal view of the upper part of a flexible ink container with a float valve serving as a retention valve and when in a normal position to ensure the variations of the atmospheric and heat pressures with the aid of the elastic counter-pressure ring which is placed underneath the seat of the retention valve.

FIG. 10 is an enlarged view of the counter-pressure ring shown in FIGURE 9.

FIGURE l1 is a longitudinal sectional view of the writing mechanism provided with a flexible ink container showing the counterweight in the hollow push-button and the prolongated ink needle passing through the entire writing mechanism.

FIGURE l2 shows a flexible inkwell with a conical seat and also shown with a sealing mouthpiece.

FIGURE 13 shows' an inkwell with an ink pumping mechanism and a conical seat for the lower part of the guide cylinder.

FIGURE 14 shows a cap for the inkwells shown in FIGURES l2 and 13, provided with an internal bore forming a key whose shape corresponds to the shape of the writing tube base.

FIGURE 15 shows a cap for the inkwells shown in FIGURES 12-13, with a flexible punctured seat for the writing tube.

FIGURE 16 shows' a liexible cap with a retention valve to be used with an ordinary inkwell, which can be applied to the breather openings at the top of the ink container.

Referring to the drawings in detail, FIGURE 1 shows a completely assembled pen including a body 10 having a threaded cap 11 screwed thereon. The ink container 12 serves as a pump cylinder, and has a pump plunger 13 actuated by means of the pump shaft 14 and head 15. The ink container 12 is provided with ink absorbing flexible capillary material 16, for example, with flexible foam plastic having open cells which at one end is attached to the pump plunger 13 and at the other end is attached to the surface of the threaded ink capillary channels 17 by welding, pasting, or by any other means. It must be observed that the capillary force of the capillary iiexible material 16 must be stronger at the end which is attached to the openings of the ink capillary channels 17 than at the end which is attached to the pump plunger 13. This increase in capillarity is obtained as the exible capillary material with open cells used for the ink container 12, is cut or otherwise formed conically and therefore, when placed inside the ink container 12 with the base against the ink capillary channels 17, this part is compressed more than the opposite part of the flexible capillary material 16, with the result that the open cells are smaller in this part and therefore have more capillary force. The threaded ink capillary channels 17 are formed in guide cylinder 18 and together with the capillary ink supply member 19 and ink needle capillary guide 20 provide a central bore in which the ink needle 21 with its counterweight 22 is guided. The counterweight 22 is' limited in its upward movement by a threaded nut 23 which is screwed on the upper end of the guide cylinder 18, and limited in its downward movement by the upper part of the capillary ink supply member 19, which also prevents the pressure of the downward movement from being transmitted on to the ink column of the ink needle capillary guide 20. In the lower part of the central bore in member 19 are a plurality of capillary radial channels 24 which conduct the ink to the ink needle capillary guide 20. The threads of the above-mentioned threaded nut 23, which is screwed on the guide cylinder 18 are of a slightly smaller diameter than the threaded capillary channels 17 of the guide cylinder 18 leaving a space free for the passage of ink. Said nut 23 also has a central bore, which guides the upper part of the counterweight 22, whose shoulder is checked in its upward movement by said nut 23. The base 25 of the writing tube 26 is screwed in the guide cylinder 18 and the ink openings 27 are formed so as to lie between the closing surfaces 28 of the base 25 and the guide cylinder 18, when these two latter members are rmly screwed together and by lightly unscrewing the base 25 the ink openings 27 are left free. The base of the writing tube 25 is also provided with a threaded or hexagonal head 29 which fits into key 30 which is formed in the top of the push-button 31 of the slide tube 32. The key 30 comprises an opening provided with circumferential notches into which the threads 29 lit. To fill the writing mechanism with ink, the same is removed from the pen body 10 by first unscrewing the cap 11 and sliding the tube 32 up over the body of member 25 until the key 30 in the push-button 31 engages the threads 29. The tube is rotated suiiciently to unscrew member 25 and expose openings 27. In the upper part of the ink container 12 immediately before the point where the pump plunger 13 reaches its extreme rearward position, there are formed a plurality of breather openings 33 for the variations of the atmospheric and heat pressures, made possible by an opening 34 in the pen body 1i) which connects the inside of the fountain pen with the normal outside atmospheric pressure. At the upper part of the ink container 12 there is formed a reinforcing head 12a of lesser diameter than said container 12. Said head is provided with a central opening 12b of hexagonal shape which serves as a guide for the hexagonal pump shaft 14, to thus avoid rotation of the pump plunger 13 and the capillary flexible material 16 in the ink container 12. This reinforcing head 12a also serves as guide for the wiring mechanism since it fits exactly into the lower part of the slide tube 32 in the cap 11. The above described -key 30 may be constructed in any other place on the cap 11 or the pen body 10 and may take any other shape so long as it will 'firmly engage threads 29 for its intended purpose.

In all fountain pens furnished with pump plungers of the usual type, it is possible to adapt them to the use of iiexible capillary material; however, in vorder to maintain the advantages of the capillary force, the breather openings 33 must be included in the construction.

The writing mechanism shown in FIGURE 6 has the same threaded capillary guide cylinder 18, counterweight 22, writing needle 21, writing tube base 25, and Writing tube 26, but is provided with a exible or collapsible wall ink container 35 which is filled with exible capillary foam plastic 36 or other exible capillary ink absorbing material. For the purpose of letting ink into the pen, there is provided a threaded bushing 37 at the top of the ink container 35, which guides and serves as a stop for the threaded push-buton 38, said push-button has a conical extension 39 and a stop bolt 40 which when unscrewed (FIG. 7) together with the plastic tube 41 situated in the neck of the ink container 35 forms an eflicient conical retention valve 42 which in its normal position, i.e., when the threaded push-button 35 and its conical extension 39 is firmly screwed down is always open to ensure free respiration according to the variations of atmospheric and heat pressures.

FIGURE 9 shows the float valve 43 which includes the body 44 and serves to prevent the leakage of ink when filling the pen and, at the same time combines with the lower seat to serve as a retention valve 45. The seat is provided with an elastic counter-pressure ring 46 having upwardly extending projections which prevent the oat body 44 by its own weight from closing same, although it allows the oat body 44 to rest in the seat when drawing ink into the pen. This ring is provided to ensure the free inlet and outlet of air for the variations of atmospheric and heat pressures.

The perforated disc 47 which is provided at the top of the flexible capillary material 16 of the flexible ink container 35, separates the capillary material 16 from retention valve 45.

In the neck of the ink container 35 above the retention valves 42 and 45, there is provided some breather openings 48 for the variation of atmospheric and heat pressures.

In fountain pens with a ball-point the writing needle is shortened sufficiently to ensure that the same does not touch the ball in the writing point in the downward movement.

FIGURE l1 shows a ball-point pen including a exible ink container with flexible capillary material, where the counterweight 22 of the ink needle Z1 is situated in the hollow push-button 49 which serves as a guide therefor. The prolongated ink needle 21 is placed inside a capillary guide spiral t) which passes through the flexible capillary material of the ink container 35a, through the inside length of the guide cylinder, through the base and a part of the writing tube 51 of the ball-point pen. The capillary guide spiral 5@ is loosely placed in the base 25 and between the threaded capillary channels 52 of guide cylinder 18 but firmly placed in the bushing 53 whose upper surface checks the downward movement of the counterweight 22. The ink openings 27 are formed as ink inlet valves with the aid of a weak elastic tube 54 firmly placed in the base 25 which lightly covers said openings 27. The base 25 is unscrewed to let ink into the ink container a in the manner previously described by means of the screw threads 29 and the corresponding key 36. After filling the ink container, the base 25 is again screwed on by hand or with a cylindrical enlargement of the base 25 surrounding the same. As well as an elastic tube valve 54 provided in the lower part of the guide cylinder 18, there is provided an upper weak elastic tube valve 55, which covers the area where the push-button 49 joins the ink container, thereby covering the openings 56 which serve as air outlet vents when the pen is being filled. The upper elastic tube valve 55 is lightly lifted to permit variations of the atmospheric and heat pressures through the openings 56.

FIGURE l2 shows a flexible inkwell 57 provided with aconical seat 58 for the lower part of the guide cylinder 18 of the writing element, the inkwell having a lid as shown in FIGURE 14. Also shown is the sealing mouthpiece 56a, with which the flexible inkwell 57 may be provided for forcing ink into the ink container through the capillary spaces between ink needle 21 and the writing tube 26.

FIGURE 13 shows an inkwell 59, provided with a pump mechanism 60, a retention valve 61, a conical seat 62'for the lower part of the writing element, and an injection chamber 63. The inkwell is provided with a cap similar to that shown in FIGURE 14.

FIGURE 14 shows the cap 64, which can be used with the inkwells shown in FIGURES l2 and 13, with the key 65 into which the notches on the writing tube base 25 fit for the purpose of facilitating the opening and closing of the ink openings 27.

FIGURE l5 shows another type of cap 66 for the inkwells shown in FIGURES 12 and 13, which permits the ink to be forced into the ink container directly through the capillary spaces between the writing tube 26 and the ink needle 21, thus obviating the use of the ink openings 27. This is made possible with the aid of the exible and elastic rubber or plastic tube 67 with its central opening 68, into which the writing tube is placed.

FIGURE 16 shows a type of cap 69 to be used with an ordinary inkwell, and which may be applied to the breather openings in the upper part of the writing element as shown in FIGURES 6, 7, and l1, and which makes the construction of the retention valves 42-55 unnecessary. This lid is formed as a ilexible and elastic rubber or plastic cap or bulb and placed with its seat 71 over the breather openings 48-56 as shown in FIGURES 6, 7, and ll. By exercising pressure on the collapsible walls of the exible cap 69, the air inside same is forced out through the retention valve 7 i) and by lessening the pressure on the cap, the air inside the ink container will be sucked out 6 through the breather openings 48 or 56, and therefore the ink will be forced into the ink container through the ink openings Z7, previously opened, or directly through the capillary spaces between the ink needle Z1 and writing tube 26.

The operation of the above described ink container provided with a flexible capillary material actuated by pump plungers for the inlet of ink, is as follows:

In order to fill the pen, the cap 11 is unscrewed and the tube 32 and the writing mechanism are removed. The ink openings 27 are made accessible by engaging the key 3i? at the top of the tube 32 with the threadsl 29 on base member 25. By slightly rotating tube 32, the member 25 is unscrewed from the lower part of the body 18 exposing the openings 27. Then by pushing the pump plunger 13 downwardly by means of the pump shaft 14 and its head 15, the flexible capillary material 16 in the ink container 12 is compressed and the air and ink is forced out through the capillary channels 17, the capillary supply member 19, the ink needle capillary guide 26 and nally out through the ink openings 27. By pulling back on the head 15 of the pump shaft 14 the compressed exible capillary material 16 expands and sucks through the ink openings 27 fresh ink into the material 16. As soon as the pump plunger 13 has been drawn fully back leaving the breather openings 33 free, the ink openings 27 can again be closed by screwing the base 25 of the writing tube 26 into the guide cylinder 18 by use of the key 30 and then the Writing mechanism can be replaced in pen body 10 and the head piece 11 screwed thereon. The fountain pen is then again in writing condition.

In the mechanism provided with a exible ink container as shown in FIGURE 6, in order to let ink into same, the threaded push-button 38 with its conical extension 39 has to be unscrewed until the stop bolt 4i) lies against the threaded bushing 37 as shown in FIGURE 7. Then, by exercising pressure on the collapsible sides of the flexible ink container 35, the air inside the same is forced out through the conical retention valve 42 and the breather openings 48 and by releasing the pressure on the container 3S, the ink will be caused by the lower pressure in the ink container 35 to enter the ink container 35 through the ink openings 27 in the base 25 of the writing tube 26. The threaded push-button 38 is then screwed down as shown in FIGURE 6 permitting the passage of atmospheric air freely through the breather openings 48.

Referring to FIGURE 9, the float retention valve 43 functions as previously described during the filling of the pen. However, when the ink container is full of ink, the seating of the valve prevents the same from leaking through the valve 43 and out through the respirations openings 43.

The upper surface of the capillary ink supply member 19, which receives the impact of the downward stroke of the counterweight 22, prevents the pressure from being transmitted to the ink column in the ink needle capillary guide 20.

When a flexible inkwell such as shown in FIGURE 12 is used for letting ink into the ink container of the writing mechanism, the cap 64 (FIG. 14) having the key 65 therein, is removed from the flexible inkwell 57, and used to unscrew the base 25 of the writing tube suiiciently to expose the ink openings 27. The writing mechanism is then placed firmly in the conical seat 58, and the inkwell 57 is turned upside down and pressure exerted on the sides of the iiexible inkwell 57 until the ink container is full of ink. Then, while maintaining pressure on the sides of the inkwell, it is turned to an upright position and the writing element removed. The pressure on the inkwell can now be released, the ink openings 27 closed, and the cap 64 replaced in the inkwell 57.

The inkwell 59 shown in FIGURE 13 is also furnished with a cap 64 similar to that shown in FIGURE 14, and when letting ink into the ink container, the cap 64 is removed from the inkwell and used in the manner just described to open the ink openings 27, with the key 65. Then, the writing mechanism is placed firmly in the conical seat 62 of the inkwell, and by pulling back on the piston of the pump mechanism 60, ink is drawn into the injection chamber 63, and when the piston is pushed downward the ink is forced into the ink container of the writing element through the ink openings 27. Since the ink is retained in the injection chamber of the retention valve 61, the pump mechanism is operated until the ink container is full of ink, then the writing mechanism is removed from the inkwell 59, the ink openings closed, and the cap replaced in the inkwell.

FIGURE shows a second type of cap 66, which may be used for the inkwells shown in FIGURES 12 and 13 and which has the advantage of eliminating the use of the ink openings 27 and key 30, since the ink is forced into the ink container directly through the capillary spaces between the writing tube 26 and the writing needle 21. As shown in the drawing, the writing tube 26 is placed firmly in the flexible and elastic rubber or plastic tube 67 of the cap 66 with the point of the writing tube passing through the central opening 68, and the ink is forced into the ink container as described in the description to FIGURES 12 and V13.

The flexible and elastic rubber or plastic cap or bulb 69 shown in FIGURE 16 eliminates the construction of retention Valves in the Writing element. This flexible cap is furnished with a seat 71, into which the upper part of the writing element'is firmly seated as shown in the drawing. In the upper part of the flexible bulb 69, there is provided a retention valve 70 through which the air is expelled, when pressure is exercised on the collapsible sides of the flexible bulb 69. When releasing the pressure, the air inside the ink container is sucked out through the breather openings and the ink will be forced by the lower pressure in the ink container to enter same through the ink openings 27, which are previously made accessible by unscrewing the base 25 with the key 30, or directly through the capillary spaces between the ink needle 21 and the writing tube 26. This operation is repeated until the ink container is full of ink, then the bulb is removed from the writing element, and the ink openings 27 closed in the known manner.

I claim:

1. A fountain pen having a body and a cap removably secured to one end thereof and a writing point at the opposite end, an ink container within said body, a compressible cellular capillary material within said container, a plunger slidably disposed in the upper portion of said container, the capillary material secured at its upper end to said plunger and at its lower end to said container, a guide tube secured to the lower end of said container beneath said capillary material, a writing tube threadedly secured to said guide tube, ink inlet openings radially disposed in the side wall of said writing tube, means for opening and closing said openings, and breather openings in said ink container to compensate for variations in atmospheric pressures.

2. A fountain pen according to claim 1, including key means for engagement with said writing tube to separate the same 'from said guide'tube and uncover the ink filling openings in said writing tube.

3. A fountain pen according to claim 1, wherein said guide tube is provided with a plurality of capillary channels along its inner wall.

4. A fountain pen according to claim 1, including ink guide means within said guide tube and writing tube.

5. A fountain pen according to claim l, wherein a capillary ink supply member is provided to cushion the downward stroke of said counterweight, thereby preventing transmission of the force of said stroke to the ink column of the ink needle capillary guide.

6. A fountain pen having a body and a cap removably secured to one end thereof and a Writing point at the opposite end, an ink container within said body, a compressible cellular material Within said container, means for compressing said material, a guide tube secured to the lower end of said container beneath said capillary material, a writing tube whose base is threadedly secured to said guide tube, ink inlet openings radially disposed in the side wall of said writing tube, key means engageable with said writing tube base opening and closing said openings, and breather openings in said ink container to compensate for variations in atmospheric pressures.

7. A fountain pen according to claim 6, including a capillary guide member extending throughout the length of said body, an ink needle within said capillary guide member, a counterweight at the end of said needle opposite the writing point, a hollow push-button secured to the upper end of said body, said counterweight slidably disposed in said push-button.

8. The fountain pen of claim 6, wherein said ink container is provided with a collapsible wall to permit compression of said capillary material.

9. The fountain pen of claim 6, including adjustable means in the top of said ink container for controlling the passage of air through said breather openings.

10. A fountain pen according to claim 6, including ink supply means apart from the pen for letting ink into the ink container thereof, said ink supply means attachable to said ink inlet openings and said breather opening to permit filling of said ink container.

l1. A fountain pen according to claim 10, wherein said -ink supply means includes seating means for the lower part of said writing tube and means for forcing ink into said ink container.

l2. A fountain pen according to claim 10, wherein said ink supply means includes suction means having a seat for receiving the upper part of the ink container whereby manipulation of said suction means will draw air out of the ink container through said breather openings'.

References Cited in the file of this patent UNITED STATES PATENTS 

1. A FOUNTAIN PEN HAVING A BODY AND A CAP REMOVABLY SECURED TO ONE END THEREOF AND A WRITING POINT AT THE OPPOSITE END, AND INK CONTAINER WITHIN SAID BODY, A COMPRESSIBLE CELLULAR CAPILLARY MATERIAL WITHIN SAID CONTAINER, A PLUNGER SLIDABLY DISPOSED IN THE UPPER PORTION OF SAID CONTAINER, THE CAPILLARY MATERIAL SECURED AT ITS UPPER END TO SAID PLUNGER AND AT ITS LOWER END TO SAID CONTAINER, A GUIDE TUBE SECURED TO THE LOWER END OF SAID CONTAINER BENEATH SAID CAPILLARY MATERIAL, A WRITING TUBE THREADEDLY SECURED TO SAID GUIDE TUBE, INK INLET OPENINGS RADIALLY DISPOSED IN THE SIDE WALL OF SAID WRITING TUBE, MEANS FOR OPENING AND CLOSING SAID OPENINGS, AND BREATHER OPENINGS IN SAID INK CONTAINER TO COMPENSATE FOR VARIATIONS IN ATMOSPHERIC PRESSURES. 